Diluted High‐Concentration Electrolyte Based on Phosphate for High‐Performance Lithium‐Metal Batteries

Abstract Lithium (Li) metal is an ultra‐high specific capacity and low potential ‘‘holy grail’’ anode for developing high energy density rechargeable Li metal batteries (LMBs), but its practical application suffers from the low Coulombic efficiency (CE) and dendritic lithium growth due to its thermodynamic instability to organic solvents. Here, we report a new diluted high concentration electrolyte (DHCE) containing lithium bis(fluorosulfonyl)imide, triethyl phosphate and fluorobenzene cosolvent, which not only guarantees lithium metal anode (LMA) with an 98.4 % high average CE over 250 cycles but greatly improves Li||NMC622 cells property (70 % capacity retention after 200 cycles at C/3 current density). Therefore, this new electrolyte can provide more possibilities for developing high‐energy‐density LMBs.